Attachment arrangement for a leaf spring compound

ABSTRACT

An attachment arrangement ( 21 ) for a leaf-spring compound ( 2 ) used as a release system ( 1 ) especially for soil-working implements, the leaf-spring compound ( 2 ) including several leaf springs ( 215, 215 ′) with substantially identical ground plans, the leaf springs ( 215, 215 ′) being held together by an attachment arrangement ( 21 ) at either end portion ( 2153 ) of the leaf springs ( 215, 215 ′), each of the end portions ( 2153 ) of each leaf spring ( 215, 215 ′) abutting supportingly in a coupling element ( 211 ) and being attached to the coupling element ( 211 ) with a clamping bolt ( 212 ), a stop element ( 213 ) and a supporting element ( 214 ), the supporting element ( 214 ) creating a clearance to an inner leaf spring ( 215 ′) and being positioned at least partially over a cut-out ( 2152 ) in the leaf springs ( 215, 215 ′).

The invention provides an attachment arrangement for a leaf-spring compound used as a release system especially for soil-working implements, the leaf-spring compound including several leaf springs with substantially identical ground plans.

In a plough with a release mechanism that is activated when a plough body meets an earthfast stone, for example, and the release mechanism is to return to a normal working position as soon as the cause of the release has been passed, a hydraulic or mechanical release system is used as a rule. One version of a mechanical release system includes a leaf-spring package, in which the releasing force can be adjusted by single leaf springs being added or removed. Leaf-spring packages of this kind are held together with bolts in the middle portion of the leaf springs. The drawback of this solution are that the bolt holes constitute a potential starting point for material cracks leading to spring ruptures. Leaf springs of this kind are known from the applicant's products over several decades.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art or at least to provide a useful alternative to the prior art.

The object is achieved through features, which are specified in the description below and in the claims that follow.

An attachment arrangement for a leaf-spring compound used as a release system especially for soil-working implements is provided, the leaf-spring compound including several leaf springs, also called a spring package, with substantially identical ground plans, but possibly with different spring characteristics, typically provided by using leaf springs of different material thicknesses. The leaf springs are held together by an attachment arrangement at either end of the leaf springs.

Each end portion of the leaf springs may be arranged in a coupling element, wherein all the leaf springs are attached to the coupling element, and the coupling element is further attached to elements constituting adjacent parts of the release system. A coupling element typically includes a bottom plate, an end wall and two opposite side walls and is thereby open in two directions, allowing the leaf springs to be inserted in these directions.

The spring package may be attached to the coupling element with a clamping bolt that projects up from a bolt hole in the bottom plate of the coupling element and through cut-outs in the end portions of the leaf springs, the cut-outs having a substantially larger extent in the longitudinal direction of the spring package than the diameter of the clamping bolt to allow relative, longitudinal motion of the individual leaf springs when they are being tensioned, possibly also having a larger transverse dimension in order to provide room for a sleeve-shaped supporting element which has been guided onto and surrounds a portion of the clamping bolt and exhibits a clearance to the cut-out in the leaf springs. The supporting element of this kind may internally be provided with threads coarser than the threads of the clamping bolt. Alternatively, the supporting element consists of a supporting plate extending between the walls of the coupling element and resting against the end portion of the inner leaf spring.

In one embodiment, the threads of the clamping bolt form an engagement means for a stop element in the form of a nut. The nut, which is provided with an internal thread diameter and pitch like those of the clamping bolt and has an external thread diameter and pitch corresponding to those of the internal threads of the sleeve-shaped supporting element, may be provided with a projecting portion and an outer end portion that forms a coupling portion arranged for engagement with a tightening tool, for example a coupling portion of an external square or hexagon shape for connection to a tightening tool, for example an open-end spanner or a hexagon socket spanner. Alternatively, the projecting portion may form the coupling portion.

Alternatively, and in combination with the plate-shaped supporting element, a smooth clamping bolt is used, provided with engagement means in the form of several transverse holes in the bolt end opposite the bolt head. The holes form alternative positions for a locking bolt. A hole giving a moderate clearance between the leaf springs of the spring package is used. The locking bolt may be secured with a securing means, typically in the form of a spring pin.

The sleeve-shaped supporting element may advantageously include a securing means in the form of an anti-rotation means, for example a peg on a projecting end portion of the supporting element, the peg being arranged to engage with a portion of a leaf spring, for example the elongated slot forming the cut-out in the end portion of the leaf spring.

When a spring package is attached by the use of the sleeve-shaped supporting element, the spring package is laid against the internal bottom surface of the coupling element, and the supporting element is brought into place in the cut-out of the spring package with the securing means in engagement with the cut-out in the spring package. While the supporting element is resting with its end portion against the bottom of the coupling element, possibly with its projecting middle portion against the spring package, the nut is screwed onto the clamping bolt and the supporting element. Because of the different thread pitches of the clamping bolt and the supporting element, the supporting element is pulled away from its abutment against the bottom of the coupling element or the spring package. Thereby, a desired clearance arises between the spring package and the projecting middle portion of the nut, and the spring package is given the possibility to creep during tensioning and relaxing. This is necessary because the different springs will have different diameters of curvature when tensioned and thereby have a need for varying movement in their attachment. The threaded connection of the nut to the supporting element provides for secure locking of the supporting element to the clamping bolt.

When attaching the spring package by the use of the plate-shaped supporting element, the spring package is slipped onto the clamping bolt. The supporting plate is slipped onto the free clamping-bolt end and is locked by the locking bolt being inserted into the one of the holes in the clamping bolt that gives a moderate clearance between the leaf springs, so that they can move relative to each other without any friction worth mentioning. The locking bolt is secured with the securing means, for example a spring pin, through the securing-means hole in the locking bolt.

The invention relates more specifically to an attachment arrangement for a leaf-spring compound used as a release system especially for soil-working implements, the leaf-spring compound including several leaf springs with substantially identical ground plans, characterized by the leaf springs being held together by an attachment arrangement at either end portion of the leaf springs, each of the end portions of each leaf spring abutting supportingly in a coupling element and being attached to the coupling element with a clamping bolt, a stop element and a supporting element, the supporting element creating a clearance to an inner leaf spring and being positioned at least partially over a cut-out in the leaf springs.

The stop element may be a locking bolt arranged to engage with an engagement means arranged in the clamping bolt in the form of one or more locking-bolt holes.

The supporting element may be formed as a supporting plate complementary to the inside of the coupling element.

The stop element may be a nut, and

-   -   the width of the cut-out may be larger than the cylindrical         diameter of the supporting element, but smaller than the         diameter of a projecting, outer end portion of the supporting         element, and the supporting element may be provided with an         internal threaded portion,     -   the nut may include a projecting portion, an external threaded         portion arranged to engage with the internal threaded portion of         the supporting element, an internal threaded portion and a         coupling portion arranged for engagement with a tightening tool,     -   the clamping bolt may be provided with an engagement portion         arranged for releasable engagement with the nut in the form of a         threaded portion arranged to engage with the internal threaded         portion of the nut, and     -   the external threaded portion of the nut may have a larger         thread pitch than the internal threaded portion of the nut.

The coupling portion may consist of the projecting portion of the nut.

The coupling portion may consist of a second end portion of the nut.

The supporting element may be provided with a securing means.

The securing means may be a peg arranged in the projecting end portion of the supporting element and be arranged to engage with a portion of the cut-out having its mouth at the end portions of the leaf springs.

Alternatively the securing means may be a spring pin arranged in a securing-means hole in the locking bolt.

In what follows, examples of preferred embodiments are described, which is visualized in the accompanying drawings, in which:

FIG. 1 shows a perspective drawing of prior-art leaf-spring compounds used on a reversible plough;

FIG. 2 shows a perspective drawing of a leaf-spring compound according to a first embodiment of the invention, viewed from below;

FIG. 3 shows, in perspective, an attachment arrangement forming an end portion of the leaf-spring compound;

FIG. 4 shows, in perspective, a section through the centre axis of an end portion of the leaf-spring compound;

FIG. 5 shows a longitudinal section through an end portion of the leaf-spring compound according to a second embodiment of the invention in a first phase of the attachment of a package of leaf springs;

FIG. 6 shows a longitudinal section through an end portion of the leaf-spring compound in a second phase of the attachment of a spring package;

FIG. 7 shows a longitudinal section through an end portion of the leaf-spring compound in a third phase of the attachment of a spring package;

FIG. 8 shows a longitudinal section through an end portion of the leaf-spring compound in a last phase of the attachment of a spring package; and

FIG. 9 shows a longitudinal section through an end portion of a leaf-spring compound after several springs have been fitted.

Connected to a so-called beam 3 of a plough, shown as a reversible plough in FIG. 1, a release system 1 has been arranged, ensuring that the plough will yield to earthfast obstructions, for example stones. In FIG. 1, the applicant's own prior-art leaf-spring compound is shown, in which the springs are held together at their middle portions.

Reference is now made to FIGS. 2-4, in which a leaf-spring compound 2 according to a first embodiment of the invention includes an attachment arrangement 21 at either end of the leaf-spring compound 2. A coupling element 211 is provided with an end wall 2111 and two opposite side walls 2112. The coupling element 211 is thereby open to receive an end portion 2153 of one or more leaf springs 215, 215′. The coupling element 211 is also provided with a bolt hole 2114 in a bottom portion 2113. In the end wall 2111, the coupling element 211 is provided with an end attachment 2115 for connection to the plough.

A clamping bolt 212 extending through the bolt hole 2114 of the coupling element 211 is provided with engagement means 2121 in the form of several locking-bolt holes.

The leaf-spring compound 2 includes several leaf springs 215, 215′, each provided with a cut-out 2152 (see FIG. 4) having a mouth with a narrowed width at either end portion 2153.

A plate-shaped supporting element 214 is substantially congruent with the inside of the coupling element 211 and is arranged to rest supportingly against an inner leaf spring 215′ of the leaf-spring compound 2.

A locking bolt 213 forms a stop element and is arranged to engage with one of the locking-bolt holes 2121 in the clamping bolt 212. When fitting the leaf-spring compound 2, the locking-bolt hole 2121 that gives a moderate mutual clearance between the end portions 2153 of the leaf springs 215, 215′ is preferably chosen. The locking bolt 213 is secured against falling out by means of a securing means 2142, shown here as a spring pin extending through a securing-means hole 2131 in the locking bolt 213.

Reference is now made to FIGS. 5-9, in which the leaf-spring compound 2 according to a second embodiment of the invention includes an attachment arrangement 21 at either end of the leaf-spring compound 2. The coupling element 211 is as described above.

In this embodiment, the clamping bolt 212 projecting through the bolt hole 2114 of the coupling element 211 is provided with an engagement means 2121 in the form of a threaded portion.

The leaf-spring compound 2 includes several leaf springs 215, 215′, each provided with a cut-out 2152 having a mouth with a narrowed width at either end portion 2153. The cut-out 2152 has a transverse dimension W (see FIG. 4).

A sleeve-shaped supporting element 214 includes a projecting end portion 2142 with a diameter D₃ (see FIG. 6 in particular). Opposite the projecting end portion 2141, an end portion forms a first abutment surface 2144 arranged to abut against the coupling element 211. The projecting end portion 2141 forms a second abutment surface 2145, which is arranged to abut against the end portion 2153 of the inner leaf spring 215′ of the leaf-spring compound 2. Internally, the supporting element 214 is provided with a threaded portion 2143. The cylindrical portion has a diameter D₁ which is smaller than the transverse dimension W of the leaf-spring cut-outs 2152. From the abutment surface 2145 of the projecting end portion 2141, a securing means 2142 in the form of a peg arranged to engage with the cut-out 2152 projects in the axial direction.

A stop means 213 in the form of a nut (see FIG. 7 in particular) is provided with an internal threaded portion 2137 arranged to engage with the clamping bolt 212. The nut 213 is also provided with an external threaded portion 2136 arranged to engage with the sleeve-shaped supporting element 214. The nut 213 also includes a projecting portion 2133 with a diameter D₂, which is larger than the diameter of the threaded portion 2143 of the supporting element 214 and forms an abutment surface 2134 that may abut against the projecting end portion 2141 of the supporting element 214. In an end portion 2135′ distant from the external threaded portion 2136, the nut 213 includes a coupling portion 2135 arranged to receive a tightening tool (not shown), for example an open-end spanner.

The external threaded portion 2136 has a larger thread pitch than the internal threaded portion 2137. This gives the effect, when the nut 213 is being screwed in, of the supporting element 214 being lifted a little so that a certain clearance forms between the second abutment surface 2145 of the supporting element 2145 and the inner leaf spring 215′ of the leaf-spring compound 2. Thereby the leaf springs 215, 215′ can move relative to each other when the leaf-spring compound 2 is being tensioned in connection with the release system 1 being activated and the leaf springs 215, 215′ being curved with different diameters. 

1. An attachment arrangement (21) for a leaf-spring compound (2) used as a release system (1) especially for soil-working implements, the leaf-spring compound (2) including several leaf springs (215, 215′) with substantially identical ground plans, characterized in that the leaf springs (215, 215′) are held together by an attachment arrangement (21) at either end portion (2153) of the leaf springs (215, 215′), wherein each of the end portions (2153) of each leaf spring (215, 215′) abuts supportingly in a coupling element (211) and is attached to the coupling element (211) with a clamping bolt (212), a stop element (213) and a supporting element (214), the supporting element (214) creating a clearance to an inner leaf spring (215′) and being positioned at least partially over a cut-out (2152) in the leaf springs (215, 215′).
 2. The attachment arrangement (21) according to claim 1, wherein the stop element (213) is a locking bolt arranged to engage with engagement means (2121) in the form of one or more locking-bolt holes arranged in the clamping bolt (212).
 3. The attachment arrangement (21) according to claim 1, wherein the supporting element (214) is formed as a supporting plate complementary to the inside of the coupling element (211).
 4. The attachment arrangement (21) according to claim 1, wherein the stop element (213) is a nut, and the width (W) of the cut-out (2152) is larger than the cylindrical diameter (D₁) of the supporting element (214), but smaller than the diameter (D₃) of a projecting, outer end portion (2141) of the supporting element (214), and the supporting element (214) is provided with an internal threaded portion (2143), the nut (213) includes a projecting portion (2133), an external threaded portion (2136) arranged to engage with the internal threaded portion (2143) of the supporting element (214), an internal threaded portion (2137) and a coupling portion (2135) arranged for engagement with a tightening tool, the clamping bolt (212) is provided with an engagement portion arranged for releasable engagement with the nut (213) in the form of a threaded portion (2121) arranged to engage with the internal threaded portion (2137) of the nut (213), and wherein the external threaded portion (2136) of the nut (213) has a larger thread pitch than the internal threaded portion (2137) of the nut (213).
 5. The attachment arrangement (21) according to claim 4, wherein the coupling portion (2135) consists of the projecting portion (2133) of the nut (213).
 6. The attachment arrangement (21) according to claim 4, wherein the coupling portion (2135) consists of a second end portion (2135′) of the nut (213).
 7. The attachment arrangement (21) according to claim 1, wherein the supporting element (214) is provided with a securing means (2142).
 8. The attachment arrangement (21) according to claim 7, wherein the securing means (2142) is a peg arranged in the projecting end portion (2141) of the supporting element (214) and arranged to engage with a portion of the cut-out (2152) which has its mouth in the end portions (2153) of the leaf springs (215, 215′).
 9. The attachment arrangement (21) according to claim 7, wherein the securing means (2142) is a spring pin arranged in a securing-means hole (2131) in the locking bolt (213). 